SQL/MP Installation and Management Guide

Planning Database Security and Recovery
HP NonStop SQL/MP Installation and Management Guide—523353-004
4-24
Using Volume-Mode or File-Mode Backup
Using Volume-Mode or File-Mode Backup
Choose a volume-mode or file-mode backup, depending on the results you want to
achieve.
For a volume-mode backup, consider these characteristics of the operation:
•
BACKUP makes a physical copy of a volume on tape. The copy includes the disk
data structures that are usually not apparent to the user. When a volume-mode
backup tape is restored, the entire disk volume, including the disk structures, is
restored and duplicates the original state of the disk.
•
Only the super ID can perform the operation.
•
A volume-mode backup tape cannot be used to restore individual files to a disk.
•
The operation copies all data files, SQL files, and SQL catalog tables. A volume-
mode backup might be useful if you need to switch from one disk drive to another.
•
Catalog consistency is assured only if the catalogs and the objects registered in
each catalog are on the same volume.
If you plan to do a volume-mode backup, see the Guardian Disk and Tape Utilities
Reference Manual.
For a file-mode backup, consider these characteristics of the operation:
•
BACKUP copies each file defined in the file set list to tape. When a file is restored
to a disk, the file is copied to the best logical free space. Restoring a file-mode
backup tape to a clean disk compacts the files to use the free space on that disk
most efficiently.
•
BACKUP does not back up the SQL catalogs unless the BACKUP command
includes the SQLCATALOGS ON option. RESTORE can restore the catalogs as
SQL tables but not as catalog tables. To recover catalogs, you should use the TMF
subsystem, as explained under Restoring Objects With TMF Recovery Operations
on page 11-11.
Because SQL/MP can introduce dependencies between disk volumes, both file-mode
and volume-mode backups can create inconsistent databases when RESTORE
operations are applied without regard to these interdependencies.
Using OBEY Command Files for Recovery
SQL/MP maintains an active data dictionary and uses the TMF subsystem to protect
the data dictionary by auditing the catalog tables. This dictionary, therefore, is subject
to the same recovery issues as SQL tables.
You must protect the database in every way possible. Although the TMF subsystem
protects the online database system, you might also want to use an offline method to
increase your protection.